Lubrication pinion modules are known from the prior art, for example from DE 102010044757 or DE 202007001440 U1, which include a gear region made from a foam material disposed on a bush. In such devices, lubricant is dispensed from the interior of the bush, or from a lubricant reservoir disposed between the bush and the gear element, to the gear element and is stored therein. Lubricant can thereby be uniformly dispensed from the gear element to a to-be-lubricated element, in particular to a gear wheel that meshes with the lubrication pinion module.
Disadvantageously, in prior art devices like this, lubricant is always present over the entire foam gear including at locations that require no lubrication. A further problem is that the fluidity (viscosity) of the lubricant typically changes with ambient- or operating-temperature. Thus, the lubricant can become very stiff (viscous) at temperatures below zero degrees Celsius, so that it can no longer be output (extruded) from the foam material at these low temperatures due to its stiffness (higher viscosity) and, consequently, the foam-material pinion hardens overall. On the other hand, at temperatures above zero degrees Celsius the lubricant can become too thin (too low a viscosity), so that too much lubricant is provided to the to-be-lubricated elements.
If the lubrication pinion module is not manufactured from foam material, then lubricant channels are usually provided in the lubrication pinion module, through which channels lubricant is pumped radially outward from the vicinity of the axis of the module. Such lubrication pinion modules are usually configured without a bush since they can rotate stably on a shaft by themselves. A particularly simple design of such a lubrication pinion module is depicted in WO 2008/113396 (U.S. Pat. No. 8,171,815), which discloses a lubrication pinion module comprised of two lubrication-pinion-module parts that are connectable to each other along a dividing plane, and at least one lubricant channel extends in the dividing plane. In this case, the lubricant channel is formed from two lubricant channels, and the lubricant-channel halves are formed at the corresponding dividing planes in the respective lubrication-pinion-module parts. If the two lubrication pinion modules are connected to each other, these lubricant channel halves can form the lubricant channels, and thus a particularly simple method of manufacturing the lubricant channels is provided. These lubrication pinion module parts are usually joined using support sleeves, screws, and washers, and the washers used in the outer lubrication pinion module parts are designed such that the pinion parts conically deform with the insertion of the washers. The lubrication pinion module is then brought back into a parallel initial shape by screwing together the pinion parts, thus achieving a sealing of the lubrication pinion module parts in the dividing plane.
One problem with known lubrication pinion modules is that sealing between two parts of such a module is very complex. This is because the to-be-sealed surfaces can be very large and because the support sleeves, washers, and screws which are required must be precisely matched to one another. However, this complex sealing arrangement is necessary since, if the sealing between the elements is inadequate, lubricant could penetrate into the dividing plane, and escape therefrom into the environment in an uncontrolled and unused manner.
A further problem with existing lubrication pinion modules is that they can only be used up to a certain rotational speed. At higher speeds, the high friction on the shaft supporting the lubrication pinion module or on the to-be-lubricated element could lead to a large temperature increase. With certain lubricants, this can lead to a degrading (excessive wear and tear) of the lubrication pinion module.